The basic thesis ofMichaelWilliams'book Unnatural Doubts is that sceptical doubts, at least of a Cartesian variety, are neither natural nor intuitive, but are, instead, the product of 'contentious and possibly dispensable theoretical preconceptions'. In particular, for Williams, scepticism arises because of a commitment to what he calls 'epistemic realism'. A fundamental thesis of my book Pyrrhonian Reflections on Knowledge and Justification is that scepticism (in its most challenging forms) is not based upon such prior theoretical commitments, but rather is the natural outcome of unrestricted exploitation of a feature already present in our everyday concept of knowledge. Specifically, our everyday epistemic practices contain a useful mechanism that raises the level of evidential scrutiny in problematic settings. However, in the absence of psychological constraints (as in Hume) or pragmatic constraints (as in Peirce), this mechanism can generate an ever-widening range of undefeated possible defeaters- and with this, radical forms of scepticism emerge.Scepticism is not the result ofmounting the wronghorse (as Williams thinks),but the result of riding a serviceable horse too hard. With respect to Williams'own contextualist response, it is not clear whether, in the end, he avoids or embraces a strong version of scepticism. He claims that Cartesian doubts arise in a particular context, namely, the context of pursuing an epistemically realistic programme. In that context, according to Williams, Cartesian scepticism is unanswerable. His central claim, I take it, is that nothing compels us to do philosophy under these contextual constraints. In arguingthisway,however,Williamsseemsto have adopted a strongversion of relativism of just the sort traditionally exploited for sceptical purposes. To the claim 'It is all a matter of context', the correct response is, 'It had better not be- at least if you are trying to refute scepticism.'Perhaps Williams can produce a strongly contextualist position that does not slide into scepticism, and perhaps his appeal- rather late his book- to externalist consideration is intended to do this.But just as it is unclear whether contextualism can avoid scepticism, it is also unclear whether externalism has force against sensibly stated (even very strong) versions of scepticism.